(a) Field of the Invention
The present invention relates to a turret condenser for microscopes and, more particularly, to an improved turret condenser for microscopes.
(b) Description of the Prior Art
Known turret condenser which enable to perform phase contrast microscopy comprise a turret and an aperture stop, which operates independently of the turret. The turret has a hole for ordinary microscopy and ring slits for phase contrast microscopy (generally, the turret is provided with different kinds of ring slits suitable for different objectives). At the time of ordinary microscopy, the hole of turret is arranged at the position of optical axis of the condenser and the aperture diameter of aperture stop is adjusted to a suitable value. At the time of phase contrast microscopy, the ring slit suitable for the objective to be used for observation is brought to the position of optical axis by rotating the turret. At the time of phase contrast microscopy, the aperture stop is not necessary and, therefore, it is kept fully opened.
When performing phase contrast microscopy after performing ordinary microscopy using the above-mentioned turret condenser, it is sometimes overlooked to fully open the aperture stop, which was stopped down at the time of ordinary microscopy, before performing phase contrast miroscopy. If phase contrast microscopy is performed without fully opening the aperture stop beforehand, the brightness of field decreases and it becomes inconvenient for observation. As a result, incorrect judgement may be sometimes caused at the time of observation. As the aperture stop does not appear in the field of view, there is such tendency to overlook the fact that the aperture stop is not fully opened and, therefore, the above-mentioned misoperation occurs very frequently.